Faster does not necessarily means worse.
Assassin's Creed was always interesting in my opinion and certainly had no "lack of content", still, they released those games way faster than SE did with FF.
And it's not just FFXIII, it's even waaaay worse with Versus XIII x-x
But I think that's okay, I'd rather have them take longer and make a beautiful game instead of doing it fast and going down to a graphics quality games have which use the Unreal Engine.
Also, where exactly has FFXIII damaged the brand?
I agree with FFXIV, but as far as I know, XIII was a success and many people are eagerly awaiting the second part.